When i change the code from
$cnf{$c}=$_;
to 
push @{$cnf{$c} }, $_;
It doesn't work.

[download]
  1. Please put your code in code tags, and normal text outside of them;
  2. What doesn't work?
Suggest me some suitable code.

What I suggested you seems suitable enough, as the following minimal adaptation of your code shows:

#!/usr/bin/perl

use strict;
use warnings;
use Data::Dumper;

my @fields=split /\n/, <<'.END';
"INVITE sip:paka@36.212.176.92 SIP/2.0
To:samir <sip:paka@36.212.176.92>
Via: SIP/2.0/udp 36.212.176.90:5060;branch=z9hG4bk_Vn
Via: SIP/2.0/udp 36.212.176.66:5060;branch=z9hG4bk_oo
From: sanjay<sip:sanjay@36.212.176.90>
Call-ID: _Vn8TZTk2H@36.212.176.90 
CSeq: 215 INVITE
Max-Forwards: 70
Contact: sanjay<sip:sanjay@36.212.176.90:5060>";
.END

my %config = (
    URI =>           { regex => qr/^INVITE\ssip:/},
    To =>            { regex => '^To:'},
    From =>          { regex => '^From:'},
    Via =>           { regex => '^Via:'},
    Call_ID =>       { regex => '^Call-ID:'},
    CSeq =>          { regex => '^CSeq:'},
    MaxForwards =>   { regex => '^Max-Forwards:'},
    Contact =>       { regex => '^Contact:'},
);

my %cnf;
foreach (@fields) {
    foreach my $c (keys %config) {
        if (/$config{$c}{regex}/) {
            push @{ $cnf{$c} }, $_;
        }
    }
}

print Dumper $cnf{Via};

__END__

[download]

Please note that I've never suggested you to blindily make that simple substitution and expect your code to work, but to change its logic in agreement with that change instead, nor am I claiming now that this is the best way to parse those headers or that I would do it like that. I hope to have given you a clue instead. Of course it won't be of much use unless you make the minimum effort to get acquainted with some basic perl first.

In reply to Re^3: How can I store two values with the same key in a hash? by blazar
in thread How can I store two values with the same key in a hash? by sanjay nayak

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.